compiler: Teach the inliner to preserve on_load functions

The inliner was ignorant of on_load functions and would discard them
(unless they were exported or referenced).

Noticed-by: Yiannis Tsiouris <[email protected]>

3 files changed, 47 insertions, 1 deletions

diff --git a/lib/compiler/src/cerl_inline.erl b/lib/compiler/src/cerl_inline.erl
index c15103999f..589685d72d 100644
--- a/lib/compiler/src/cerl_inline.erl
+++ b/lib/compiler/src/cerl_inline.erl
@@ -1262,8 +1262,9 @@ i_receive_1(E, Cs, T, B, S) ->
 i_module(E, Ctxt, Ren, Env, S) ->
     %% Cf. `i_letrec'. Note that we pass a dummy constant value for the
     %% "body" parameter.
+    Exps = i_module_exports(E),
     {Es, _, Xs1, S1} = i_letrec(module_defs(E), void(),
-                                module_exports(E), Ctxt, Ren, Env, S),
+                                Exps, Ctxt, Ren, Env, S),
     %% Sanity check:
     case Es of
         [] ->
@@ -1276,6 +1277,27 @@ i_module(E, Ctxt, Ren, Env, S) ->
     E1 = update_c_module(E, module_name(E), Xs1, module_attrs(E), Es),
     {E1, count_size(weight(module), S1)}.
 
+i_module_exports(E) ->
+    %% If a function is named in an `on_load' attribute, we will
+    %% pretend that it is exported to ensure that it will not be removed.
+    Exps = module_exports(E),
+    Attrs = module_attrs(E),
+    case i_module_on_load(Attrs) of
+	none ->
+	    Exps;
+	[{_,_}=FA] ->
+	    ordsets:add_element(c_var(FA), Exps)
+    end.
+
+i_module_on_load([{Key,Val}|T]) ->    
+    case concrete(Key) of
+	on_load ->
+	    concrete(Val);
+	_ ->
+	    i_module_on_load(T)
+    end;
+i_module_on_load([]) -> none.
+
 %% Binary-syntax expressions are too complicated to do anything
 %% interesting with here - that is beyond the scope of this program;
 %% also, their construction could have side effects, so even in effect
diff --git a/lib/compiler/test/compilation_SUITE.erl b/lib/compiler/test/compilation_SUITE.erl
index 664582a3a8..408fd5ed53 100644
--- a/lib/compiler/test/compilation_SUITE.erl
+++ b/lib/compiler/test/compilation_SUITE.erl
@@ -159,6 +159,7 @@ split({int, N}, <<N:16,B:N/binary,T/binary>>) ->
 ?comp(convopts).
 ?comp(otp_7202).
 ?comp(on_load).
+?comp(on_load_inline).
 
 beam_compiler_7(doc) ->
     "Code snippet submitted from Ulf Wiger which fails in R3 Beam.";
diff --git a/lib/compiler/test/compilation_SUITE_data/on_load_inline.erl b/lib/compiler/test/compilation_SUITE_data/on_load_inline.erl
new file mode 100644
index 0000000000..322843b61e
--- /dev/null
+++ b/lib/compiler/test/compilation_SUITE_data/on_load_inline.erl
@@ -0,0 +1,23 @@
+-module(on_load_inline).
+-export([?MODULE/0]).
+-on_load(on_load/0).
+-compile(inline).
+
+?MODULE() ->
+    [{pid,Pid}] = ets:lookup(on_load_executed, pid),
+    exit(Pid, kill),
+    ok.
+
+on_load() ->
+    Parent = self(),
+    spawn(fun() ->
+		  T = ets:new(on_load_executed, [named_table]),
+		  ets:insert(T, {pid,self()}),
+		  Parent ! done,
+		  receive
+		      wait_forever -> ok
+		  end
+	  end),
+    receive
+	done -> ok
+    end.